Pericardial fixation with 0.6% glutaraldehyde is usually assessed by measuring the temperature of shrinkage of the tissue. In vitro studies with animal pericardium have shown the maximum response to be obtained after brief immersion (10 min). The study aim was to evaluate the effect of glutaraldehyde immersion time (range: 3 min to 6 months) on temperature of shrinkage of human pericardium. Fresh untreated human pericardium was used as control. As in previous studies with animal pericardium, glutaraldehyde increased the temperature of shrinkage of human pericardium; the optimal glutaraldehyde fixation time, by measuring temperature of shrinkage, was 100 ± 0.77 min. Our results inferred that 10 min was insufficient for ‘correct’ fixation of human pericardium.